Thrombophilia: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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In healthy people, the hemostatic balance is the result of the interaction of procoagulant (clot-promoting), anticoagulant and fibrinolytic components. Numerous factors, including congenital, acquired, and external, can shift the balance toward hypercoagulability, which leads to blood clots in the veins [eg, deep vein thrombosis (DVT)], arteries (eg, myocardial infarction, ischemic stroke) or chambers heart. A thrombus can cause blood flow to be disturbed at the site of a thrombus formation or to separate and block a distant vessel (eg, with pulmonary embolism, stroke).
Causes of the thrombophilia
Mutations of genes that increase the propensity to venous thromboembolism include mutation of the V factor of Leiden, at which resistance to activated protein C occurs; mutation of the gene prothrombin 20210, protein C deficiency, protein S, protein Z, antithrombin.
Acquired violations predisposing to the development of venous or arterial thromboses, such as heparin-induced thrombocytopenia / thrombosis, the presence of antiphospholipid antibodies and (possibly) hyperhomocysteinemia resulting from deficiency of folic acid, vitamin B 12 or B 6.
Some diseases and external factors can increase the risk of developing thrombosis, especially in combination with one of the genetic defects mentioned above.
Blood stasis associated with surgical or orthopedic surgery, immobility due to paralysis, heart failure, pregnancy, obesity increase the risk of venous thrombosis.
Branch cells, especially with pro-myelocytic leukemia, lung, breast, prostate, and GI tracts predispose to the development of venous thrombosis. They are able to initiate blood hypercoagulation by secreting the protease activating factor X, expressing the tissue factor on the surface of the membrane or including both of these mechanisms.
Sepsis and other severe infections are accompanied by an increase in tissue factor expression on monocytes and macrophages, which may increase the risk of venous thrombosis.
Oral contraceptives containing estrogen increase the risk of arterial and venous thromboembolism, but the degree of risk in modern low-dose regimens is low.
Atherosclerosis predisposes to the development of arterial thrombosis, especially in places of vessel stenosis. The detachment of an atherosclerotic plaque and the entry into the blood of content rich in tissue factor, initiates the adhesion and aggregation of platelets, leads to the activation of coagulation factors and provokes the development of thrombosis.
[Diagnostics of the thrombophilia
The complex of studies aimed at the search for hereditary pathology includes the determination of the functional activity of molecules of natural anticoagulants in blood plasma and the determination of specific gene anomalies. Testing begins with a group of screening tests followed by (if necessary) specific studies.
Treatment of the thrombophilia
The methods of treatment of thrombosis depend on the localization of the thrombus. It is always necessary to take into account the presence of predisposing factors. In some cases, the situation is clinically obvious (for example, recent surgery or trauma, prolonged immobilization, oncological disease, generalized atherosclerosis). If there are no obvious predisposing factors, then in the future search it is necessary to follow the cases of venous thrombosis in the family history, the manifestation of more than one venous thrombosis, myocardial infarction or ischemic stroke before the age of 50 years, or unusual localization of venous thrombosis (for example, cavernous sinus, mesenteric veins). At least half of all patients with spontaneous deep vein thrombosis have a genetic predisposition.